1. Field of the Invention
This invention relates to well treatment operations, and more specifically to subterranean formation fracturing operations. The invention is particularly useful in fracturing operations carried out on low permeability gas formations where the formations are partly comprised of fine grain particles such as silt, clay, silicate, or a combination thereof. In fracturing such formations, stabilization of fine particles is important to minimize formation permeability reduction. It is also important to minimize the amount of fluid leaking off to the formation during the fracturing operation, thus reducing the amount of relative permeability blockage and decreasing the time required to pump back the lost fluids before the desired hydrocarbon fluids can be produced. An additional benefit of the process of the invention is that a reduced amount of conventional lost circulation material is needed.
2. The Prior Art
U.S. Pat. Nos. 4,660,640; 4,735,265 and 4,785,883 to Hoskin et al. describe a method of controlling permeability by injecting the reaction product of an alkali metal silicate and an organic hydroxy compound such as polyvinyl alcohol. These references do not suggest using the compositions to stabilize fine silt particles in a formation fracturing operation.
European Patent Application 89302558.5 describes shale-stabilizing drilling fluid additives which are similar in many respects to the materials useful in carrying out the process of this invention. The reference does not suggest using the materials to stabilize a formation to be fractured, or to reduce fluid leak-off from a fracturing fluid.
Lost circulation prevention materials are commonly used in fracturing operations.